void main() {
  String name = '张三';
  print(name);
  name = '李四';
  print('当前的用户名：${name}');
  print('当前的用户名：${name.length}');

  //  使用/n换行符
  String poemStr = '白日依山尽\n黄河入海流\n欲穷千里目\n更上一层楼';
  print(poemStr);
  // 还有一种换行模式
  String song = '''
    Hiding from rain and snow,
    Looking at crowed from our around go
''';
  print(song);
}
